Uncooled engines will run at very high pressures and temperatures, enabling more fuel energy to push the piston, with the rest in the much hotter exhaust gas, where it can be retrieved to increase performance. Using exhaust heat energy recovery systems, as in F1 race cars, they will have efficiencies of up to 75%, depending on number / type of recovery systems used. That compares with 5% to 20% real-world efficiencies for current smaller ICEs; up to 45% for large ones using some exhaust heat energy. Pistons and cylinders of industrial ceramic are in thermally / acoustically heavily insulating casings, effectively silencing the engine. Typically, an electrical generator would be coupled to the engine inside the casing to make a gen-set. With no plumbing for cooling or for piston-cylinder oil systems, engines can be ’snap-in’ cartridges. Equipment does not need to be towed to a repair facility; engines are changeable in the field, a game changer.